<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title></title>
  <script src="/vue.js"></script>
</head>
<body>
  <div id="root">
    <button @click="handleClick">load component</button>
  </div>
  <script>
    var vm = new Vue({
      el: '#root',
      methods: {
        async handleClick() {
          const { default: add } = await import('./app.js')
          add(900)
        }
      },
    })
  </script>
</body>
</html>